Adaptive Prediction Emerges Over Short Evolutionary Time Scales.

Adaptive prediction is a capability of diverse organisms, including microbes, to sense a cue and prepare in advance to deal with a future environmental challenge. Here, we investigated the timeframe over which adaptive prediction emerges when an organism encounters an environment with novel structure. We subjected yeast to laboratory evolution in a novel environment with repetitive, coupled exposures to a neutral chemical cue (caffeine), followed by a sublethal dose of a toxin (5-FOA), with an interspersed requirement for uracil prototrophy to counter-select mutants that gained constitutive 5-FOA resistance. We demonstrate the remarkable ability of yeast to internalize a novel environmental pattern within 50-150 generations by adaptively predicting 5-FOA stress upon sensing caffeine. We also demonstrate how novel environmental structure can be internalized by coupling two unrelated response networks, such as the response to caffeine and signaling-mediated conditional peroxisomal localization of proteins

Data from: Divergence in DNA photorepair efficiency among genotypes from contrasting UV radiation environments in nature

Populations of organisms routinely face abiotic selection pressures, and a central goal of evolutionary biology is to understand the mechanistic underpinnings of adaptive phenotypes. Ultraviolet radiation (UVR) is one of earth’s most pervasive environmental stressors, potentially damaging DNA in any organism exposed to solar radiation. We explored mechanisms underlying differential survival following UVR exposure in genotypes of the water flea Daphnia melanica derived from natural ponds of differing in UVR intensity. The UVR tolerance of a D. melanica genotype from a high-UVR habitat depended on the presence of visible and UV-A light wavelengths necessary for photoenzymatic repair of DNA damage, a repair pathway widely shared across the tree of life. We then measured the acquisition and repair of cyclobutane pyrimidine dimers, the primary form of UVR-caused DNA damage, in D. melanica DNA following experimental UVR exposure. We demonstrate that genotypes from high-UVR habitats repair DNA damage faster than genotypes from low-UVR habitats in the presence of visible and UV-A radiation necessary for photoenzymatic repair, but not in dark treatments. Because differences in repair rate only occurred in the presence of visible and UV-A radiation, we conclude that differing rates of DNA repair, and therefore differential UVR tolerance, are a consequence of variation in photoenzymatic repair efficiency. We then rule out a simple gene expression hypothesis for the molecular basis of differing repair efficiency, as expression of the CPD photolyase gene photorepair did not differ among D. melanica lineages, both in the presence and absence of UVR

Divergence in DNA photorepair efficiency among genotypes from contrasting UV radiation environments in nature

Populations of organisms routinely face abiotic selection pressures, and a central goal of evolutionary biology is to understand the mechanistic underpinnings of adaptive phenotypes. Ultraviolet radiation (UVR) is one of earth\u27s most pervasive environmental stressors, potentially damaging DNA in any organism exposed to solar radiation. We explored mechanisms underlying differential survival following UVR exposure in genotypes of the water flea Daphnia melanica derived from natural ponds of differing UVR intensity. The UVR tolerance of a D. melanica genotype from a high-UVR habitat depended on the presence of visible and UV-A light wavelengths necessary for photoenzymatic repair of DNA damage, a repair pathway widely shared across the tree of life. We then measured the acquisition and repair of cyclobutane pyrimidine dimers, the primary form of UVR-caused DNA damage, in D. melanica DNA following experimental UVR exposure. We demonstrate that genotypes from high-UVR habitats repair DNA damage faster than genotypes from low-UVR habitats in the presence of visible and UV-A radiation necessary for photoenzymatic repair, but not in dark treatments. Because differences in repair rate only occurred in the presence of visible and UV-A radiation, we conclude that differing rates of DNA repair, and therefore differential UVR tolerance, are a consequence of variation in photoenzymatic repair efficiency. We then rule out a simple gene expression hypothesis for the molecular basis of differing repair efficiency, as expression of the CPD photolyase gene photorepair did not differ among D. melanica lineages, in both the presence and absence of UVR

Presumed ocular histoplasmosis syndrome in a commercially insured population, United States.

PURPOSE:To describe epidemiologic features of patients with presumed ocular histoplasmosis syndrome (POHS) in the United States using insurance claims data and compare POHS patients with and without choroidal neovascularization (CNV). DESIGN:Retrospective cohort study. METHODS:Patients with International Classification of Diseases, Ninth Revision, Clinical Modification diagnosis codes for histoplasmosis retinitis on an outpatient claim in the 2014 IBM® MarketScan® Commercial Database and the Medicare Supplemental Database who were enrolled for at least 2 years after the POHS code. MAIN OUTCOME MEASURES:Data related to testing, treatment, and direct medical costs. RESULTS:Among >50 million total MarketScan enrollees, 6,678 (13 per 100,000) had a POHS diagnosis code. Of those, 2,718 were enrolled for 2 years; 698 (25%) of whom had a CNV code. Eleven of the 13 states with the highest POHS rates bordered the Mississippi and Ohio rivers. CNV patients had significantly more eye care provider visits (mean 8.8 vs. 3.2, p<0.0001), more ophthalmic imaging tests, higher rates of treatment with anti-vascular endothelial growth factor injections (45% vs. 4%, p<0.0001), and incurred higher mean total yearly costs ($1,251.83 vs.$251.36, p<0.0001) than POHS patients without CNV. CONCLUSIONS:Although the relationship between Histoplasma and POHS remains controversial, geographic patterns of POHS patient residence were consistent with the traditionally reported range of the fungus. CNV in the context of POHS was associated with additional healthcare use and costs. Further research to understand POHS etiology, risk factors, prevalence, and complications is needed, along with early diagnosis and treatment strategies

Survival_data

Data shown in Fig. 1. Number of starting animals and number of surviving animals after UV-B exposure and subsequent exposure to photorepair radiation (light) or no radiation (dark)

DNA damage data

Data shown in Fig 2A & 2B, with statistical results shown in Table 1. Data are absorbance values from ELISA for cyclobutane pyrimidine dimers (CPDs) in DNA

qPCR data for photorepair gene

Raw Ct (cycle threshold) values from quantitative PCR, used to calculate relative expression values for photorepair gene shown in Fig. 3. Loci abbreviations are as follows: phr = photorepair, EF1A = elongation factor 1-alpha (reference gene), ATUB = alpha-tubulin (reference gene), G3PD = glyceraldegyde-3-phosphate dehydrogenase (reference gene

Source pond GPS coordinates

Source pond GPS coordinate

DNA damage data (dark treatment)

Data shown in Fig 2C. Data are absorbance values from ELISA for cyclobutane pyrimidine dimers (CPDs) in DNA

Carotenoid content

Carotenoid data shown in figure in Supporting Information